German Laid-open Specification DE 10 2007 024 243 A1 discloses a double-walled insulated cup made of paper material and comprising an inner cup having a generally truncated conical wall and a pot-type bottom wall. The wall and the bottom wall are joined together by means of a peripheral edge frame in a liquid-tight manner. The peripheral edge frame is flared in its bottom region in a direction contrary to that of the truncated conical shape of the inner cup. When a number of cups are stacked together, the bottom edge of the peripheral edge frame of the upper cup can be supported against a bottom shoulder located in the bottom half of the wall of the inner cup. In the top half of the inner cup, a top shoulder can be provided, from which the outside diameter of the inner cup increases up to the top edge of the inner cup, as regarded from the bottom wall of the inner cup. The insulated cup comprises an outer sleeve having a likewise truncated conical wall. The outer sleeve lies against the external wall of the inner cup above the top shoulder thereof and likewise lies against the wall of the inner cup below the bottom shoulder thereof. A roll-in entity that is rolled in toward the inner cup can be provided at the bottom end of the outer sleeve in order to increase the distance between the inner cup and the outer sleeve in this region.
It is an object of the present invention to improve a double-walled insulated cup made of paper material and a method for the fabrication of a double-walled insulated cup.
According to the invention, a double-walled insulated cup made of paper material is provided for this purpose, which cup comprises an inner cup having a generally truncated conical wall and a pot-type bottom wall, these being joined together by means of a peripheral edge frame or skirt, and further comprising an outer sleeve, the inner cup having a top shoulder in its top half and a bottom shoulder in its bottom half, and the outside diameter of the inner cup at the level of its top shoulder increases up to the top edge of the inner cup, as regarded from the bottom wall of the inner cup, and the outer sleeve rests against the inner cup at least in the region of its top shoulder and extends at least to a bottom edge of the peripheral edge frame and lies against the peripheral edge frame at least in the region of the bottom edge thereof, and the outside diameter of the outer sleeve at the level of the bottom edge of the peripheral edge frame is smaller than the inside diameter of the inner cup just above the bottom shoulder and is greater than the inside diameter of the inner cup just below the shoulder.
The invention enables an increased distance to be achieved between the inner cup and the outer sleeve in a double-walled insulated cup, which results in improved insulating properties thereof. The cup has an enhanced appearance, since the outer sleeve extends to the bottom edge of the peripheral edge frame, and the peripheral edge frame and the bottom wall are hidden from view. At the same time, this increases the printable surface of the outer sleeve. Furthermore, the stability of the cup, more specifically, the stability of the peripheral edge frame, can be increased, since the peripheral edge frame is stiffened by the outer sleeve resting against the peripheral edge frame at least in the region of the bottom edge thereof. Furthermore, improved firmness of the base of the cup can be achieved, since a larger amount of formable material is present in the region of the standing area of the cup, and the standing area of the cup is increased. Apart from these advantages, the insulated cup of the invention is capable of being stacked by means of the peripheral edge frame in a well-proven way. The outer sleeve can also be used for stacking the cup in that the outer sleeve rests against the outside of the peripheral edge frame so that the peripheral edge frame need not be flared or need not be flared to any great extent. Finally, the double-walled insulated cup of the invention is easier to fabricate than insulated cups known in the prior art, since the narrow end of the outer sleeve does not have to slide beyond the outer edge of the peripheral edge frame, but can instead rest directly against the same. This considerably facilitates the fabrication of the insulated cup and, more specifically, the process of sliding the outer sleeve over the inner cup.
In a development of the invention, the outer sleeve is wrapped around the bottom edge of the peripheral edge frame.
In this way, the outer sleeve can be attached in a simpler and more stable manner to the peripheral edge frame. The standing area of the insulated cup is thus formed by the bottom edge of the outer sleeve. Such a standing area is larger than the bottom edge of the peripheral edge frame alone so that the insulated cup exhibits improved standing stability.
In a development of the invention, the outer sleeve is attached to an internal surface of the peripheral edge frame. In this way, the join between the outer sleeve and the peripheral edge frame is hidden from view. For example, the outer sleeve is sealed or glued to the internal surface of the peripheral edge frame. Only the outer sleeve extending down to the bottom edge of the cup is then visible on the outside of the peripheral edge frame. The outer sleeve need not rest against an external surface of the peripheral edge frame so that a cup having a very pleasing shape is produced, because the outer sleeve has a continuous truncated conical shape extending from its top end below a mouth bead down to the bottom end. An outer sleeve of such shape is, furthermore, easy to print on.
In a development of the invention, the outer sleeve is attached to the inner cup in the region of the top shoulder.
In this way, the outer sleeve can be attached easily to the inner cup, and the outer sleeve is thus held at a distance from the inner cup between the top shoulder and the bottom edge of the peripheral edge frame such that satisfactory insulating properties can be achieved.
In a development of the invention, the outer sleeve has a truncated conical shape and extends from an underside of a mouth bead disposed on the inner cup down to the bottom edge of the peripheral edge frame.
In this way, an insulated cup having a very pleasing shape is provided that has, at the top edge thereof, the mouth bead of the inner cup and, below the mouth bead, the outer sleeve. The outer sleeve has a continuous truncated conical shape extending down to the bottom edge of the cup.
In a development of the invention, the outer sleeve rests flat against the peripheral edge frame at least partially in a contact region that extends upwardly from the bottom edge of the peripheral edge frame.
In this way, the outer sleeve can be joined very securely to the peripheral edge frame by means of its flat contact therewith. The outer sleeve can rest flat either against an external surface of the peripheral edge frame or against an internal surface thereof, after the outer sleeve has been wrapped. The outer sleeve and the peripheral edge frame can be joined together by means of a heat seal or glue or a hot-melt adhesive, for example.
In a development of the invention, the outside diameter of the outer sleeve in a retracted region located above the contact region decreases more sharply than the taper of the truncated conical outer sleeve above the retracted region.
In this way, the inside and outside diameters of the outer sleeve above the region, in which the outer sleeve rests against the outside of the peripheral edge frame, can be more sharply tapered than those of the truncated conical shape of the outer sleeve. In this way, a comparatively large distance ensuring satisfactory insulating properties can be maintained between the outer sleeve and the inner cup up to just above the contact region.
In a development of the invention, the outer sleeve rests flat against the inner cup in a region extending from the top shoulder of the inner cup up to the underside of a mouth bead disposed at the top end of the inner cup.
In this way, the outer sleeve can also be attached very securely to the inner cup in the top region of the same. The top shoulder can serve as a filling mark for the cup so that there is not normally any liquid located above the top shoulder, and thus the reduced insulating properties in this region due to the lack of an air gap between the outer sleeve and the inner cup do not constitute a disadvantage.
The object of the invention is also achieved by a method for the fabrication of a double-walled insulated cup made of paper material, which method includes the following steps:                fabricating an inner cup having a generally truncated conical wall and a pot-type bottom wall, these being joined together by means of a peripheral edge frame,        fabricating a generally truncated conical outer sleeve by joining together the longitudinal edges of a blank for the outer sleeve,        sliding the outer sleeve over the inner cup in a direction extending from the bottom wall of the inner cup toward the wide end of the inner cup, and        attaching the narrow end of the outer sleeve to the peripheral edge frame of the inner cup.        
The fabrication of the insulated cup can be facilitated by prefabricating the outer sleeve from a blank shaped as a circular ring segment to form a truncated conical sleeve, and by sliding it in this truncated conical state over the inner cup proceeding from the bottom wall thereof. Fitting the outer sleeve is particularly facilitated on account of the fact that the narrow end of the inner cup need not slide beyond the peripheral edge frame, but rather the narrow end of the outer sleeve is attached to the peripheral edge frame of the inner cup itself. The narrow end of the outer sleeve and the peripheral edge frame are readily accessible for this purpose.
In a development of the invention, the narrow end of the outer sleeve is attached to the peripheral edge frame by wrapping the narrow end around the bottom edge of the peripheral edge frame.
In this way, a very stable join between the outer sleeve and the peripheral edge frame can be achieved. If the join between the outer sleeve and the peripheral edge frame, achieved by a simple wrapping process, namely by non-positively joining the peripheral edge frame to the outer sleeve, is not sufficiently stable, the outer sleeve and the peripheral edge frame can be additionally attached to the internal and/or external surface of the peripheral edge frame by means of a heat seal, glue or a hot-melt adhesive. For example, the outer sleeve can be joined, at least partially, to an external and/or internal surface of the peripheral edge frame after the narrow end of the outer sleeve has been wrapped around the bottom edge of the peripheral edge frame.
In a development of the invention, the outer sleeve is slid over the inner cup until a bottom edge of the outer sleeve is at the level of the bottom edge of the peripheral edge frame, and the narrow end of the outer sleeve is attached to the peripheral edge frame by joining the internal surface at the bottom edge of the outer sleeve to the external surface of the peripheral edge frame.
In this way, the outer sleeve can be attached securely to the peripheral edge frame without requiring the narrow end of the outer sleeve to be wrapped around the peripheral edge frame.
Additional features and advantages of the invention are revealed in the claims and in the following description of preferred embodiments of the invention, with reference to the drawings. Individual features of the different embodiments shown and described can be arbitrarily combined with each other, as required, without going beyond the scope of the present invention.